The present invention relates to compositions for textile applications. More particularly, the present invention relates to silicone compositions which adhere durably to textiles.
Silicones are used in the textile industry due in part to the unique benefits that they impart to the materials, such as softness. One problem in the industry is lack of durability in fabric treatments. In many applications, the silicone is deposited on textile surfaces and is often held only by weak physical forces. For instance, treatment of textiles with silicones containing amino or quaternary functional groups can result in benefits that display some durability. However, these polymers are believed to bond ionically or through hydrogen bonding with cellulosic surfaces. Because the interactive forces are weak, the benefits of silicone treatments are often short lived.
It is therefore desirable to produce silicone compositions which can be used to treat textiles and provide durable benefits. Thus, silicone products are constantly being sought which can both adhere durably to textiles as well as impart textile benefits appreciated by consumers.
The present invention provides a method for treating a cellulose-containing substrate comprising contacting a silicone composition comprising at least one polysiloxane or silicone resin containing at least one functional group comprising at least one dialkylacetal group, at least one anhydride group, at least one reactive group, or combinations thereof with the cellulose-containing substrate; and
curing the silicone composition on the cellulose-containing substrate at a temperature in a range between about 25xc2x0 C. and about 200xc2x0 C.
The present invention further provides a formulation comprising an aqueous mixture or non-aqueous mixture of at least one polysiloxane or silicone resin containing at least one functional group comprising at least one dialkylacetal group, at least one anhydride group, at least one reactive group, or combinations thereof and optionally, at least one catalyst;
wherein the formulation adheres to a cellulose-containing substrate when the formulation is cured at a temperature in a range between about 25xc2x0 C. and about 200xc2x0 C. when the formulation is applied to the cellulose-containing substrate.
The present invention includes a silicone composition which includes at least one polysiloxane or silicone resin containing at least one functional group capable of interacting with cellulose. The functional group in the silicone composition of the present invention enables adhesion of the polysiloxane or silicone resin to cellulose-containing surfaces under surface treatment conditions. The functional group comprises at least one dialkylacetal group, at least one anhydride group, at least one reactive group, or combinations thereof.
The present invention includes silicone compositions having the formula:
MaMxe2x80x2bDcDxe2x80x2dTeTxe2x80x2fQg
where the subscripts a, b, c, d, e, f and g are zero or a positive integer, subject to the limitation that the sum of the subscripts b, d and f is at least one; where M has the formula:
R13SiO1/2,
Mxe2x80x2 has the formula:
xe2x80x83(X)hR23-hSiO1/2,
D has the formula:
R32SiO2/2,
Dxe2x80x2 has the formula:
(X)(2-i)Ri4SiO2/2,
T has the formula:
R5SiO3/2,
Txe2x80x2 has the formula:
(X)SiO3/2,
and Q has the formula SiO4/2, where subscript h is in a range between 1 and 3; subscript i is 0 or 1; each R1, R2, R3, R4, R5 is independently at each occurrence a hydrogen atom, C1-30 alkyl, C1-22 alkoxy, C2-22 alkenyl, C6-14 aryl, C6-22 alkyl-substituted aryl, or C6-22 aralkyl, any of which groups may be halogenated, for example, fluorinated to contain fluorocarbons such as C1-22 fluoroalkyl, or may contain amino groups to form aminoalkyls, for example aminopropyl or aminoethylaminopropyl, or may contain polyether units of the formula (CH2CHR6O)k where R6 is independently in each repeat unit CH3 or H and xe2x80x9ckxe2x80x9d is in a range between about 4 and about 50; X, independently at each occurrence, represents a functional group that is capable of causing durable interactions with cellulose-containing substrates. The term xe2x80x9calkylxe2x80x9d, as used in various embodiments of the present invention, is intended to designate both normal alkyl, branched alkyl, aralkyl, and cycloalkyl radicals. Normal and branched alkyl radicals are preferably those containing in a range between about 1 and about 30 carbon atoms, and include as illustrative non-limiting examples methyl, ethyl, propyl, isopropyl, butyl, tertiary-butyl, pentyl, neopentyl, hexyl, and dodecyl. Cycloalkyl radicals represented are preferably those containing between about 4 and about 12 ring carbon atoms. Some illustrative non-limiting examples of these cycloalkyl radicals include cyclobutyl, cyclopentyl, cyclohexyl, methylcyclohexyl, and cycloheptyl. Preferred aralkyl radicals are those containing between about 7 and about 14 carbon atoms. These include, but are not limited to, benzyl, phenylbutyl, phenylpropyl, and phenylethyl. Aryl radicals used in the various embodiments of the present invention are preferably those containing between about 6 and about 20 ring carbon atoms and contain at least one monocyclic or polycyclic moiety wherein a polycyclic may comprise fused or linked rings. Some illustrative non-limiting examples of these aryl radicals include phenyl, biphenyl, and naphthyl. An illustrative non-limiting example of a suitable halogenated moiety is trifluoropropyl.
According to the present invention, one important class of functional groups that is capable of causing durable interactions with cellulose-containing substrates is the dialkylacetal group. These groups have the general formula: 
wherein R7 and R8 are alkyl groups as defined above for R1, R2, R3, R4 and R5 and where j is in a range between about 2 and about 10. The carbon-carbon bonds can be interrupted by aryl groups or other ring structures. Aryl groups used in the various embodiments of the present invention are preferably those containing in a range between about 6 and about 20 carbon atoms and containing at least one monocyclic or polycyclic moiety wherein a polycyclic may comprise fused or linked rings. The aryl groups also may incorporate one or more substituents that are compatible with the applications described in this invention. Exemplary substituents include but are not limited to halogens, alkyls, aralkyls, alkaryls, aryls, alkoxy groups, and aryloxy groups.
In another embodiment of the present invention, xe2x80x9creactive groupxe2x80x9d as used herein includes any C1-C250 alkyl, aryl, or alkylaryl group where the C1-250 group can be interrupted by or substituted with aromatic groups or aromatic-containing groups and which contains a leaving group that is capable of interacting with cellulose. The C1-250 group may also contain one or more heteroatoms such as O, N, or S. Furthermore, the C1-250 group may be unsubstituted or substituted with heteroatoms such as halogen. An exemplary reactive group comprises a chlorobenzyl moiety. Other examples of reactive groups of the present invention include, but are not limited to: 
where
r is in a range between about 1 and about 10, preferably 2 or 3;
s is in a range between about 0 and about 100, preferably 4 to 20;
t is in a range between about 0 and about 100, preferably in a range between about 0 and about 20, and most preferably 0;
u is in a range between about 1 and about 10, preferably 1;
v is in a range between about 1 and about 10, preferably 2 or 3;
w is 1 or 2;
x is 1 or 2;
Z is O, NOH, NOR or NR, preferably O;
L is a leaving group;
wherein R is independently at each occurrence hydrogen (H), C1-30 alkyl, C1-22 alkoxy, C2-22 alkenyl, C6-14 aryl, C6-22 alkyl-substituted aryl, or C6-22 aralkyl where the C can be unsubstituted or substituted with heteroatoms such as oxygen (O), nitrogen (N), sulfur (S) or halogen;
wherein R9 is independently at each occurrence hydrogen (H), C1-30 alkyl, C1-22 alkoxy, C2-22 alkenyl, C6-14 aryl, C6-22 alkyl-substituted aryl, C6-22 aralkyl, or fused ring system which may or may not be fused to the phenyl group where the C can be unsubstituted or substituted with heteroatoms such as O, N, S or halogen. R9 is preferably H. If R9 represents an aryl group, it can be fused to the ring in Formulas (I) through (IV);
A is O, NOH, NOR, NR or S, preferably O;
B is O, NOH, NOR, NR or S, preferably O or NR and most preferably O;
and where the polysiloxane or the silicone resin is bound to the (CR2)r (Formula I and II), (CR2)v (Formula III), or (CR2)w (Formula IV). Any of the linker structures shown in Formulas (I) through (IV) can also be interrupted with cycloaliphatic rings or aromatic rings. Substituents on the phenyl group of formulas (I), (II), (III), and (IV) may be present at any free valence site. The polysiloxane or silicone resin may or may not contain other functionalities by substitution at silicon atoms either the same as or distinct from those bound to the reactive groups described above, such as amine-, polyether-, alkyl-, or heteroalkyl-containing groups.
Illustrative leaving groups (L) include halides such as chloride, bromide and iodide; tosylate, mesylate, phosphate; cyclic leaving groups (that is, those in which the leaving group remains bound to the fragments illustrated as bound to L in formulas I-IV) or other cyclic leaving groups containing at least one heteroatom; and other leaving groups known to those skilled in the art. Preferred leaving groups are bromide, chloride, and iodide.
In an additional embodiment of the present invention, the polysiloxane or silicone resin is substituted with one or more anhydride groups. The anhydride of the present invention typically includes, for example, five membered ring anhydrides and six membered ring anhydrides. Five membered ring anhydrides are preferred. Examples include succinic, maleic and phthalic anhydrides as well as nadic anhydride (cis-5-norbornene-endo-2,3-dicarboxylic anhydride) and benzophenone tetradicarboxylic anhydride. Any group which can be chemically bound to a polysiloxane or silicone resin and which contains a five membered ring anhydride is suitable. Importantly, also covered in the scope of this invention is the substitution of a polysiloxane or silicone resin with one or more groups that are capable of forming an anhydride under substrate treatment or cure conditions.
The number of functional groups on a polysiloxane or silicone resin in the composition that are capable of causing durable interactions with cellulose-containing substrates is at least one. In preferred embodiments the average number of functional groups on a polysiloxane or silicone resin is in a range between about 1 and about 100, more preferably in a range between about 1 and about 20, still more preferably in a range between about 2 and about 10.
The polysiloxanes or silicone resins of the present invention are typically prepared by the hydrosilylation of an organohydrogen silicone and an unsaturated molecular precursor to the dialkylacetal group, reactive group, anhydride functional group, or combination thereof wherein the organohydrogen silicone has the formula:
MaMHbDcDHdTeTHfQg
where the subscripts a, b, c, d, e, f and g are zero or a positive integer, subject to the limitation that the sum of the subscripts b, d and f is one or greater; M, D, T and Q are defined as above;
MH has the formula:
R23-hHhSiO1/2,
DH has the formula:
H2-1R41SiO2/2,
TH has the formula:
HSiO3/2,
where each R2 and R4 is independently as defined above; and subscript h and subscript i are defined above.
Hydrosilylation is typically accomplished in the presence of a suitable hydrosilylation catalyst. The catalysts preferred for use with these compositions are described in U.S. Pat. Nos. 3,715,334; 3,775,452; and 3,814,730 to Karstedt. A preferred catalyst contains platinum. Persons skilled in the art can easily determine an effective amount of platinum catalyst. Generally, an effective amount is in a range between about 0.1 parts per million and about 100 parts per million of the total silicone composition.
The organohydrogen silicone compounds that are the precursors to the compounds of the present invention may be prepared by the process disclosed in U.S. Pat. No. 5,420,221. The ""221 patent discloses the redistribution of polydimethylsiloxane polymers with organohydrogen silicone polymers and optionally, added chain stopper, to provide a silicone with randomly-distributed hydride groups using a Lewis acid catalyst, preferably a phosphonitrilic compound. Hydride-terminated polymers can be made in related equilibration reactions.
Synthesis of the polysiloxane or silicone resin may also be performed by other methods known to those skilled in the art, for example, the hydrosilylation of a monomer such as methyldichlorosilane could be followed by co-hydrolysis with the appropriate dialkyldichlorosilane and optionally, chlorotrimethylsilane.
It is to be noted that as pure compounds, the subscripts describing the organohydrogen siloxane precursor and the hydrosilylation adduct of the present invention are integers as required by the rules of chemical stoichiometry. The subscripts will assume non-integral values for mixtures of compounds that are described by these formulas. The restrictions on the subscripts heretofore described for the stoichiometric subscripts of these compounds are for the pure compounds, not the mixtures.
The polysiloxane or silicone resin typically has a molecular weight in a range between about 100 and about 6,000,000, preferably in a range between about 250 and about 150,000, more preferably in a range between about 500 and about 100,000, and most preferably in a range between about 500 and about 75,000.
In one embodiment of the present invention, a polysiloxane- or silicone resin-containing composition includes a preponderance of a specific linear, branched, cross-linked, or cyclic polysiloxane or silicone resin. In other embodiments of the present invention, a polysiloxane- or silicone resin-containing composition comprises a mixture of polysiloxanes, mixture of silicone resins, or mixtures of polysiloxanes and silicone resins which may include linear, branched, cross-linked, and cyclic species. Also, suitable compositions may comprise one or more polysiloxanes, silicone resins, and mixtures thereof which may contain adventitious amounts of other species at a level in a range between about 0.0001 wt % and about 5 wt % based on total silicon-containing species, for example, arising during the synthesis process for said polysiloxanes or silicone resins. In illustrative examples, suitable compositions may contain adventitious amounts of D4, or species containing Sixe2x80x94H, Sixe2x80x94OH, Sixe2x80x94O-alkyl bonds, and mixtures thereof.
Silicone compositions of the present invention that include at least one polysiloxane or silicone resin and at least one functional group typically impart durable benefits to materials such as textiles, including cellulose-containing surfaces such as natural fibers and regenerated fibers including blends. A particular advantage of the present invention is that the described functional groups enable the silicone composition to adhere to a cellulose-containing surface.
The silicone compositions can be delivered to a substrate, for example a cellulose-containing surface, from any appropriate aqueous or non-aqueous formulation, for example a water mixture or a water and catalyst mixture which can contain the silicone composition in a range between about 0.01% by weight and about 99% by weight based on the total formulation. The silicone composition may also be applied to the substrate as the neat material. Typically, the formulation may also include a catalyst, a typical example of which is an acid or a base. The catalyst is typically present in a range between about 0.01% and about 15% by weight based on the total formulation.
After application of the silicone composition onto the substrate, the composition can be cured over a period in a range between about 5 minutes and about 2 hours. Typically, the cure temperature is in a range between about 25xc2x0 C. and about 200xc2x0 C. Alternatively, the substituted silicone or silicone resin can be applied to the substrate neat and cured in the same manner.